Plasma myosin and creatine kinase time-course after a concentric-eccentric field exercise

Area of Science:

• Exercise Physiology
• Biochemistry
• Sports Medicine

Background:

• Strenuous exercise, particularly involving eccentric muscle actions like downhill running, can cause skeletal muscle damage.
• Biomarkers are crucial for quantifying exercise-induced muscle damage and understanding recovery.
• Creatine kinase (CK) is a commonly used marker, but its time course may not fully capture the extent of muscle injury.

Purpose of the Study:

• To compare the time course of plasma creatine kinase (CK) activity and beta myosin heavy chain (beta MHC) concentration following prolonged exercise.
• To investigate the potential of beta MHC as a sensitive marker for skeletal muscle damage after acute exercise.

Main Methods:

• Five healthy male volunteers completed a 22.3 km run involving both concentric (uphill) and eccentric (downhill) phases.
• Blood samples were collected pre-exercise, immediately post-exercise, 5 hours post-exercise, and at 1, 2, 3, 4, 5, and 7 days post-exercise.
• Plasma CK activity and beta MHC concentration were measured in all collected samples.

Main Results:

• Plasma CK activity peaked transiently within 24 hours of recovery for all subjects.
• Plasma beta MHC elevation was delayed, with peak concentrations observed on the second or third day post-exercise.
• A significant positive correlation (P < 0.001) was found between individual CK and beta MHC values.

Conclusions:

• Plasma beta MHC levels rise later than CK levels following acute exercise.
• Beta MHC demonstrates potential as a reliable biomarker for assessing skeletal muscle damage induced by strenuous exercise.
• The findings suggest that beta MHC may provide a more comprehensive assessment of muscle injury over a longer recovery period than CK alone.